Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

<image>

The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

<image>

In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

<image>

Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in PYTHON):

Solution:
class Step:
	direction = ''
	value = 0
	def __init__(self,a1,a2):
		self.direction = a1
		self.value = a2

n,m = map(int,raw_input().split())
flag = True
if n > m:
	flag = False
	
if flag == True:
	ls = [[0 for i in range(m)]for j in range(n)]
else:
	ls = [[0 for j in range(n)]for j in range(m)]

for i in range(n):
	mid = map(int,raw_input().split())
	if flag == True:
		ls[i] = [mid[j] for j in range(m)]
	else:
		for j in range(m):
			ls[j][i] = mid[j]

if flag == False:
	n,m = m,n
ans = 0
step = []
maxx = max(ls[0])
minn = min(ls[0])
if maxx != minn:
	ans += minn
	for i in range(minn):
		step.append(Step('row',1))
	for i in range(m):
		ls[0][i] -= minn
		if ls[0][i] != 0:
			for mm in range(ls[0][i]):
				step.append(Step('col',i+1))
			for j in range(1,n):
				ls[j][i] -= ls[0][i]
			ans += ls[0][i]
			ls[0][i] = 0
else:
	ans += maxx
	for i in range(minn):
		step.append(Step('row',1))
for i in range(1,n):
	maxx = max(ls[i])
	minn = min(ls[i])
	if maxx != minn:
		ans = -1
		break
	else:
		ans += maxx
		for j in range(maxx):
			step.append(Step('row',i+1))
if ans == -1:
	print ans
else:
	print ans
	for item in step:
		if flag == True:
			print item.direction,item.value
		else:
			if item.direction == 'row':
				print 'col',item.value
			else:
				print 'row',item.value